(Reuters) – San Francisco-based 137 Ventures said it raised $137 million for its second fund, underscoring the eagerness of investors to buy shares in start-ups before they hold initial public offerings.

The firm, which buys private-company shares from company founders, early employees, and other investors, counts companies such as data-analytics business Palantir, space-exploration firm SpaceX and blog site Tumblr among its portfolio. Tumblr sold to Yahoo! Inc last year for $1.1 billion.

With start-ups staying private longer than a decade ago, many investors believe they are missing out on big gains they could have once captured through public shares.

In the past, the opportunity to invest in start-ups went largely to venture capitalists.

But increasingly, start-up companies are allowing early shareholders to cash out through tightly controlled sales to approved buyers such as 137 Ventures or other outlets such as SecondMarket.

Investors in 137 Ventures tend to be institutions, wealthy individuals, family offices and the like, said Justin Fishner-Wolfson, co-founder and managing partner.